Direct Attached Storage (DAS) is an abbreviation for Direct Attached Storage, which means that an external storage device is directly connected to a computer through a connecting cable. DAS this direct way to solve the single server storage space expansion, high-performance transmission needs, and a single external storage system capacity, has been from less than 1TB, developed to 2TB, with the introduction of large-capacity hard drive, A single external storage system capacity will rise. DAS depends on the server, which itself is a hardware stack, without any storage operating system.
DAS program in the external storage device currently mainly refers to RAID, JBOD, etc., RAID into Chinese means "redundant array of independent disks," sometimes referred to as disk arrays (Disk Array). RAID refers to multiple types, capacity, interface, and even the same brand of dedicated hard disk or hard disk into a common array, so that it can in a fast, accurate and secure way to read and write disk data, so as to improve the data read Speed and safety of a means.
JBOD (just a bunch of disks) translated into Chinese can be a simple disk bundles, often referred to as Span. Span is logically grouping several physical disks one after the other to provide a large logical disk. Span access performance is exactly the same as access to a single disk.